I say this, mind, as someone who really doesn't know shit about shit: it ain't quantum physics:
Search engines assign quality rankings based on "who" links to your page, as that indicates that your site is interesting/authoritative, meaning other people might like to be able to find it.
"Who" = 1)how many links, and 2)what are the pageranks of the people linking to you (if the cool kids like you, you must be cool).
Barry's site had a high rating because a lot of people linked to him and because many of the people linking to him had a high ranking themselves.
This is what the company that owns amptoons.com purchased: the ranking. Given to him by the people who linked to his site and based in part on their own site's reputation. A porn company needs reputable people to link to its sites, which they accomplished by making the weblink farm on Barry's site.
See? Not that hard to understand or explain, not even for a luddite, artistic or otherwise.
Sorry to re-recap what Heart has said elsewhere, better.
Now, HERE's the interesting part: the big-boy capitalism of most every purported "non-luddite" explaining the above, with their own conclusion attached (an excuse Barry himself provided):
See? No harm done, because Porn Company A appearing higher than Porn Company B doesn't hurt anyone!
Forget the myriad reasons to avoid getting on this logic train in the first place (exploiting your friends without their knowledge or consent comes to mind, as does the spurious "presumed amorality" of helping someone to exploit women more efficiently).
Let's talk about that conclusion.
Anyone who is able to understand enough to justify search engine optimizing on a capitalist basis, knows enough to be aware of what that translates into, on the ground, for women and children.
They just don't see it. Because they looked at the "bottom line," and for them, the bottom line is cash. Where does the cash go? What does it pay for? It helps one company compete against another company. Oh, well, that's good and normal, right?
Have you (YOU, Gentle Reader) ever tried to search for information on the internet and accidentally received porn as a result?
If this has never happened to you, you are certainly exempt for shrugging your shoulders at the net effect of selling a site to an SEO.
If this has happened to you: did you like it? Did you, despite not consenting to see the porn, "really want it" after all? Every time? If you like and use porn, and support the right to use and distribute it, do you also support the right to only be confronted with pornography upon seeking it out? Don't you believe in consent for all things sexual?
Do you want your kid, or a kid you know, to be hit across the face with rape porn while doing his/her homework? Courtesy Melissa at Womensspace, here's a potentially-triggering link (will bring up print-dialog box, as I selected that view in order to avoid the graphic).
If that's not what you want, how do you plan to prevent that from happening? Do you plan to install, and count on schools and libraries installing, a porn-blocking program that can, and in current use commonly does, block up to 50% of legit, health-oriented webpages when searching for controversial or sex-related terms like "safe sex," "condom," "gay," and "abortion?"
Are search engine-fooling tricks by pornographers harmful to women and children? I'll SAY they are. They're also harmful to the "freedom" that the pro-Amp's-autonomy contingent seems to value so very much.
Like most fake capitalists, though, and like Barry himself, they seem to carry forward the implication of a free market and a free society only so far - when it protects their interests, these ideas are valued. When it means shouldering the full cost of what you're buying into (or selling!), suddenly the "knowledge," technical and otherwise, disappears into thin air. In this way, one can claim ignorance of how one's fake capitalism is harming others and reducing freedom.
How VERY revolutionary.